Stucci Crossover

[Guest roofer1]

I know this has been asked in the past, went online and searched, found different opinions/recommendations - am still somewahat confused.

 

Question; 2002 LeMans, stock with the exception of Mistral Slip-Ons, will my machine benefit with a Stucci Crossover, not only with h.p., but with sound, torque etc. increase?

 

Additionally, will I have to change to a PC III?

 

Thanks.

 

Roofer1

[helicopterjim R.I.P.]

Without delving into the PCIII issue (yet) I found that the Mistral crossover benefits midrange and overall balance whereas the Stucchi is better suited for topend power. Since I have FBF pistons that already significantly boost midrange I choose the Stucchi although I did try both.

 

I don't know what affect they will have on the sound as you already have the Mistral mufflers.

 

I feel the PCIII is worth it for any setup.

[Paul Minnaert]

well it will be louder with non stock crossovers.

[dlaing]

Additionally, will I have to change to a PC III?

81236[/snapback]

No, you will have to tune the ECU with TuneBoy

I am half kidding. I simply favor TuneBoy over PCIII, but most seem to favor PCIII.

Some people run without TuneBoy or PCIII or one of the other options, but I would not recommend it after changing mufflers, crossovers, etc.

 

The Stucchi also boosts midrange, but not as much as the Mistral x-over

[Guest golden goose]

I ordered the Ti Mistrals and Mistral x-over from Agostini's when I first got the bike. Being US Spec, the stock mapping was horrible. I took it to the dealer who promptly messed with the TPS position. I droped him, and I heard MGNA did too. I ordered a PC, but mine is a PCII. Had Mickey Cohen (formerly with OC Motorsports) dyno it in for me. Added a little more juice to the lower rev region after I got it back and it has been great ever since. Mickey got 79 rear wheel hp out of this, which is just about right for a 90hp crank donk.

[jrt]

yes, it'll run better. do it if you have the chance.

[mdude]

repeating myself here, but:

HT Moto in Germany tested the V11 with the MG Titan pipes (quite similar to the Mistrals, I think?) in various combinations a couple of years back. They found that for regular driving one should leave the stock expansion box, which gave the engine a more relaxed and grunty feel. The exp. box had the overall best effect on both torque and hp, except for the highest of revs.

 

With Stucchis you got top end power, but lost ooomph in the low revs.

 

I used my stock exp. box and was very pleased with the result. loads of ooomph, but I still have a Mistral x-over which I will try in the spring.

[dlaing]

http://www.moto-one.com.au/performance/v11sport.html before and after stucchi comarison same bike

and

http://www.visi.com/~moperfserv/more_mg.htm before and after stucchi, but different bike(so less accurate)

Both indicate that the Stucchi cross-over loses power almost nowhere and gains significant mid-range.

[Guest ratchethack]

FWIW - The dyno pulls done by Lofgren/Manley that Dave cited above were the basis for my decision to go with the Stucchi X-over, and my "seat-o'-the-pants dyno" has confirmed 'em. Well worth the extra midrange torque gains with FBF oval carbons and PC III, IMHO. Sounds better too...

[Guest rosso mandello]

Hey, does anyone out there know, what is wrong with the stock resonator. I pulled mine apart, did not find much in it, just both the top and the button covered with an 1/3 inch thick steelwool mat held in place with "holeplate".

I pulled it all out, an my velder is now closing it again. Now that I have removed anything that may have caused any resonance in the exhaust airflow I cannot wait to get it assembled and back on the road.

I drive open airbox, K&N, "stock resonator", Mistral round carbon,

Has anyone tried to alter an Agostini cross over, make better connection betwin the 2 pipes?

And the snow is still laying outside......

[Guest ratchethack]

Rosso, IMHO the resonant characteristics of V-11 exhausts are extremely complex and not entirely understood. What seems to be clear from what I've read about exhaust flow analysis is that reflected back-pressure wave pulses from surfaces and angles in the exhaust system interact and reflect back upstream, causing different effects in the cylinder head before the exhaust valve closes at different throttle openings and loads. These wave resonances affect the quality of the cylinder charge. Seemingly small differences in shape of the crossover can have definite effects on torque curves. The design of the stock X-over was undoubtedly based on what would get it past sound emission restrictions. What can be known with certainty is that there are measurable effects of different exhaust components on a dyno. From what I understand, the exhaust gas wave pulse resonance is also affected by the characteristisc of the intake plumbing, probably mostly due to the quality of the filling charge to begin with. The removal of the holeplate and packing from the stock X-over may or may not have a desirable result in terms of torque and power curves, but your experiment sounds interesting!

 

I think somebody else did this awhile back, but I can't remember the outcome.

[belfastguzzi]

Hey, does anyone out there know, what is wrong with the stock resonator.

81341[/snapback]

It looks absolutely terrible. The horrid pressed-up sardine-can gives no pleasure whatsover, quite the opposite.

 

Apart from that, it sounds like – nothing.

 

And as well, the stock box and ecu provide a nasty hole in the motor's midrange.

 

Did I mention that it looks horrible and sounds terrible?

[luhbo]

My understanding is that removing the steel wool will not reduce the tendency for any resonance frequencies. Au contraire, you removed the damping elements, so any resonancies probably will become even sharper.

 

If you take a closer look at the mentioned dyno results and investigations you will find that the stock crossover is not the worst solution. It seems to be better than the Mistral or Agostini x-over at least.

 

Personally I really appreciate the mellow tone this part gives together with open cans. The other solutions are sounding to hard for my ears, to much Ducati.

 

I'm happy with my standard x-over and can't find anything wrong at it.

 

Hubert

[Guest ratchethack]

If you take a closer look at the mentioned dyno results and investigations you will find that the stock crossover is not the worst solution. It seems to be better than the Mistral or Agostini x-over at least.

Hubert, "better" and "worse" will mean different things to different riders here.

 

I agree with you in your analysis of the above charts if your focus is only on power and torque peaks. If you're racing, this is likely where your attention will be.

 

But being a non-racing Road Geez, however, my focus was not at all on the peaks, but rather on the shape of the torque curves in the mid-range.

 

Allow me to offer the method behind this madness:

 

According to the Lofgren/Manley torque comparo, the stock crossover gives up ~3 ft-lb of torque to the Stucchi at 4500 RPM. This wouldn't seem to be much in real-world road riding, except for 2 factors:

 

1. Consider the shape of the stock torque curve and its' pronounced "hole" at 4500 RPM.

 

2. 4500 to 5500 RPM, (with frequently launching out of this range to 7000-8000), is where I spend by far and away the greater part of my riding for great stretches of time, with next to ZERO time at WOT at the power peak. When I use the throttle the most, this is exactly the RPM range where I whack it open and exactly where I want the smoothest and flattest torque output.

 

I reckon I can probably go months without ever hitting the power peak at WOT, and that's probably for less than a second at a time, so I reckon what happens to the curves at the peaks (both torque and power) doesn't matter nearly as much as what happens between 4500-5500 RPM. But that's just me.

 

What made the most significant difference to me when I fit the Stucchi X-over is that I found I was no longer having to "climb out" of that pronounced "hole" in the stock torque curve when accelerating in each gear. Take a look at how steep the stock torque curve is on the up-side of that "hole" when you come out of it. IMHO, this dip and the abruptness of the curve coming out of it is the "achilles heel" of an otherwise fairly smooth, broad, and road-usable torque curve of the stock V-11 motor. The Stucchi takes me off that steep part of the curve in the RPM range where I use the motor the most.

 

You've no doubt noticed on this chart that the stock X-over has a ~1 ft-lb advantage over the Stucchi at 5500 RPM and another ~1 ft-lb advantage at 7500 RPM. This "trade-off" was clear to me before I made the "leap" to the Stucchi. I've been very pleased with the overall "smoothing" of the torque response. It's been a practical choice, and well worth the trade.

 

BAA, TJM, & YMMV

[motoguzznix]

I agree that the standard crossover is not the worst solution.

A have a Dyno graph of my 2000 V11 with the std and the Stucchi crossover. The mufflers were my modified stock cans (see the "unpacking the cans" thread) which caused a 3 HP gain.

 

 

 

The stuchi is the upper red lines which only caused slight gains from 4500 upwards.

The std crossover is the blue lines below. Torque below 4300 is much better.

The black/green lines below is with std crossover/mufflers. The stepped power and torque curves from 4000 are typical for the standard mufflers. Note that this line ist not directly comparable to the lines above becuse of a CR of 9.6 : 1 instead of 9.15 std and a slightly advanced cam timing.

The gains with the stucchi crossover might be greater with a more freeflowing muffler. In this configuration the stucchi ist not worth the money spent, especially for driving on the streeet.

I did not swap back to the standard crossover because I will try a more freeflowing exhaust in the future.